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Cheap vaccine eradicates new cases of meningitis A

By Andy Coghlan

It has taken just six months for a cheap new vaccine against meningitis A to work its magic&colon; reducing the number of new cases in three west African countries to almost zero.

The outcome is a huge boost for a part of the world where meningitis A accounts for 90 per cent of all meningitis cases and where epidemics periodically kill tens of thousands. In 2009, between 6000 and 8000 people died and 55,000 contracted the disease in Nigeria alone.

“It’s all looking very promising,” says Marie-Pierre Preziosi of the World Health Organization, head of a long-term project to roll out the new vaccine, dubbed MenAfriVac, to all countries in Africa’s notorious “meningitis belt”, which stretches through 25 countries from Senegal to Sudan.

So far, no recipient of the vaccine has been infected, and the few cases that have occurred in treated areas were unvaccinated visitors from neighbouring areas.

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The most comprehensive programme is in Burkina Faso, a landlocked country in west Africa where 20 million individuals aged 1 to 29 received the jab last year. Preziosi says there have been no cases of meningitis A in those vaccinated, compared with the usual 100 to 200 cases expected in six months, even when there is no epidemic.

A similar picture emerged in neighbouring Mali and Niger, which six months ago vaccinated people in zones considered most at risk for meningitis A, as a prelude to population-wide vaccinations.

Cheap and potent

MenAfriVac is much cheaper than existing meningitis A vaccines, at 50¢ compared with &dollar;120 per dose. It is also more potent. Unlike conventional vaccines, which are based on sugars resembling those on the surface of Neisseria meningitides, a bacterium that causes meningitis, the new vaccine splices the sugars to a carrier protein that is better at stirring up the body’s immune system. “It makes the immune response much more vigorous,” says Marc LaForce, director of the global Meningitis Vaccine Project, which developed MenAfriVac.

Antibodies against the bacterium continue to be produced long after vaccination, providing hope that a single jab may be enough to give lifelong protection.

Nevertheless, it will be a long haul extending the vaccine to all countries at risk. Later this year, vaccinations will begin in Cameroon, Chad and Nigeria.

In an analysis based on the early results, LaForce and Jean-Marie Okwo-Bele of the WHO estimate that giving the vaccine in just seven countries could prevent a million cases over a decade and save &dollar;300 million in the costs of treatment and lost ability to work. Many people who survive the disease are left disfigured or disabled, and need long-term care and treatment&colon; brain damage occurs in 20 per cent of cases, for example.

They warn that much more money, an additional &dollar;475 million, is needed to extend the jabs to between 250 and 300 million children and young adults in all 25 countries within the meningitis belt over the next five or six years.